Precision and linearity of analog temperature sensors for industrial IoT devices

Temperature measurement still presents specific challenges in embedded systems. Since off the shelf microcontrollers also include simple analog inputs, they are widely used in embedded IIoT (Industrial Internet of Things) devices. The analog inputs of such controllers typically have a low resolution, not appropriate for measuring the output of special purpose sensors (e.g., Negative Temperature Coefficient-(NTC)). This paper analyses and compares methods for temperature measurement based on signal conditioning and linearization circuits for thermocouple, NTC, RTD (Resistance Temperature Detector) and semiconductor sensors, offering a set of experimental results obtained without initial calibration or any other software compensation of the initial errors.